I have been pumping since my girl was 2 months old, she is 21 months old and I am still pumping. I used to wash the pump parts daily and kept them in the fridge when not pumping. Gradually the time between washings extended to 2 days, 3 days, etc. I usually wash the pump parts 1x a week, but have gone many times washing them 1x every 2 weeks. Keep in mind though that I keep my fridge very cold, almost freezing. I bought a fridge thermometer to be sure it wasn't borderline dangerous. Buy one at the hardware store for a couple of bucks. Well worth it to be sure. Also a freezer thermometer for freezing milk (that is another topic though). I used to sterilize every time I washed (when baby was younger), but now I only sterilize one a month or so, or if the pump parts touched something questionable (believe it or not, I am bit of a germaphobe). I still hand wash my pump parts with bottle brushes that can get into the crevices of the parts, otherwise, if not scrubbing the parts thoroughly, the milk "film" does not come off. If you rub your fingers and you can still feel it kind of "greasy", the parts are not clean. I used to sterilize the parts every time I washed when baby was younger but gradually got away from it. I usually pump anywhere from 1x to 6x a day. In any case, storing the pump parts in the fridge lessened the need to wash so often and it saved me!!! Imagine washing 1x a week, much easier!!!
The logic behind this weekly washing is that milk can be stored in the refrigerator for up to 8 days, so the pump parts should be fine too. I haven't had any problems with the milk. My baby has been drinking refrigerated and frozen milk since she was 4 months old.
Edited by msveggie - 10/4/11 at 10:32pm